I found ticket 358380 of yours and went ahead and reviewed it.
You mentioned that the support tech didn't use his name in his replies. In every single reply from David I saw his name in the footer of the message. If you can send me over a screenshot of where you don't see it that would be great so I can verify we don't have internal issues with the helpdesk not sending replies properly.
As for the abbreviation, most of his replies were quite on par with normal except the ones which required little in a response. For example, you asked for the version of a particular software we installed, and he replied with a simple sentence stating the version.
Let me know if you have any questions or concerns